Integrated heat recovery boiler

ABSTRACT

An integrated heat recovery boiler having two independent gas paths and two means for the generation of steam. The combination of duel gas paths within the same apparatus provides a cost-efficient mechanism to increase the heat energy output of a waste-heat recovery system.

This application claims priority from U.S. Provisional PatentApplication No. 62/633,563 filed on Feb. 21, 2018.

FIELD OF THE INVENTION

The invention relates to water tube boilers, and more specifically, heatrecovery water-tube boilers.

BACKGROUND OF THE INVENTION

Gas turbines and reciprocating engines are often used to drive anelectrical generator in order to generate electricity. Such an enginecan also be coupled with an energy recovery device that generatesadditional energy. The exhaust or heat output of the engine is capturedin order to recover energy that would otherwise be lost. A water-tubeboiler can be used in this type of energy recovery system in order toconvert the heat from the engine to steam or hot water. The steam canthen be used to generate additional electricity, to drive other devices,or for whatever purpose may be desired.

Certain applications require greater amounts of steam than can begenerated through the heat recovery process alone. This problem has beenconventionally addressed through the addition of a duct burner to thesystem to further heat the gas output from the engine. The duct burnerrelies upon supplementary firing to increase thermal input, and,commensurately, steam production.

The problem, however, is that the manufacture of boiler systems havingduct burners substantially increases capital costs which often rendersuch a design economically unfeasible. It would be advantageous,therefore, to provide a waste heat recovery boiler system which providesfor an increased amount of steam production while reducing the designand manufacturing costs of such a unit.

The instant invention solves the foregoing problem by providingadditional thermal input without the need for a duct burner in combinedheat and power applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a transverse view of an integrated heat recovery steam boiler.

FIG. 2 is a transverse view of an integrated heat recovery hot waterboiler.

FIG. 3 is a transverse view of an alternate embodiment of an integratedheat recovery steam boiler.

FIG. 4 is a transverse view of a second alternate embodiment of anintegrated heat recovery steam boiler.

FIG. 5 is a transverse view of a third alternate embodiment of anintegrated heat recovery steam boiler.

DETAILED DESCRIPTION

The invention comprises an integrated heat recovery boiler having twoindependent gas paths and two means for the generation of steam.

Referring to FIG. 1, the invention comprises a water-tube boiler 100having two gas paths 110, 120 separated by a dividing structure orbarrier 130. The boiler recovers energy from engine or turbine outputbut also utilizes a traditional burner, within the same housing,whenever excess steam is needed. Specifically, a first section 110 ofthe boiler 100 only receives the gas or exhaust coming from an engine orturbine. This portion 110 of the boiler uses the heat from the gas orexhaust to generate steam which is ultimately separated and/or collectedin the steam drum 140. The boiler 100 further includes a second section120, essentially a small boiler, which can be used to generateadditional steam.

The sections are divided by a separating structure 130 which can be ametallic wall, e.g., carbon steel plate, or an insulation board, or acombination of both. The wall 130 separates the sections 110, 120 andprevents heat transfer between sections.

In the steam application, shown in FIG. 1, the upper and lower drums arein-line so that the water-tubes can be arranged to recover heat in aseparate pass. In that arrangement, the two sections 110, 120 utilizethe same steam drum 140 and the same mud drum 150. It will be noted, asseen in FIG. 2, that the design for hot-water applications relies upontwo upper and two lower drums thereby providing two independent circuitsfor the movement of water within the respective sections.

FIGS. 3-5 illustrate alternate embodiments of the invention for use insteam applications. These alternate embodiments employ a split-lowerdrum 150, 160 arrangement for use in applications with unbalanced heattransfer between the heat recovery section and the combustion section.

The combination of duel gas paths within the same apparatus, andobviation of the need for a duct burner, provides additional capacity ata reduced cost. One example of an application of such a device today isin the construction of power microgrids. Microgrids typically use smallturbines and similar engines for power generation and then couple thosewith heat recovery units in order to make the system more efficient. Theinvention disclosed herein can be used to increase efficiency whilereducing the overall cost of implementation of the power generationsystem.

While the invention has been described in reference to certain preferredembodiments, it will be readily apparent to one of ordinary skill in theart that certain modifications or variations may be made to the systemwithout departing from the scope of invention claimed below anddescribed in the foregoing specification.

What is claimed is:
 1. A dual path integrated boiler comprising a firstheat recovery boiler assembly and a second conventional boiler assemblywith both assemblies situated in parallel in a housing and substantiallyseparated by a dividing structure wherein each assembly includes anindependent gas pathway for the introduction and transmission of thermalenergy required for the generation of steam.
 2. An integrated waste heatrecovery system comprising: a heat recovery boiler section and aconventional hot water boiler section disposed in a single enclosure;said heat recovery section comprising an upper drum, a lower drum, aninlet for the acceptance of heat input, an outlet, and a plurality ofboiler tubes; said conventional section comprising an upper drum, alower drum, an inlet, an outlet, a plurality of boiler tubes, and acombustion chamber defined by a portion of said boiler tubes; and, aseparating structure between said heat recovery section and conventionsection whereby said sections are independent and heat transfer betweensections is restricted.
 3. The system of claim 2 wherein said separatingstructure is composed of metal.
 4. The system of claim 2 wherein saidseparating structure is composed of an insulating material.
 5. Thesystem of claim 2 wherein said separating structure is composed of acombination of metal and insulating material.
 6. The system of claim 2wherein said heat recovery system is a gas turbine heat waste heatrecovery system and said inlet for the acceptance of heat input providesfor the acceptance of exhaust gases from a gas turbine engine.
 7. Anintegrated waste heat recovery system comprising: an upper drum; a lowerdrum; a heat recovery section having an inlet, an outlet, and aplurality of boiler tubes which connect said upper drum and said lowerdrum; a conventional boiler section having an inlet, an outlet, aplurality of boiler tubes which connect said upper drum and said lowerdrum, and a combustion chamber defined by a portion of said plurality ofboiler tubes; a barrier between said plurality of boiler tubes in saidheat recovery section and said plurality of boiler tubes in saidconventional section whereby heat transfer between said sections isrestricted.
 8. The system of claim 7 wherein said barrier is composed ofmetal.
 9. The system of claim 7 wherein said barrier is composed of aninsulating material.
 10. The system of claim 7 wherein said barrier iscomposed of a combination of metal and insulating material.
 11. Thesystem of claim 7 wherein said heat recovery system is a gas turbineheat waste heat recovery system and said inlet for the acceptance ofheat input provides for the acceptance of exhaust gases from a gasturbine engine.
 12. An integrated waste heat recovery system comprising:a shared upper drum; a heat recovery section having a first lower drum,an inlet, an outlet, and a plurality of boiler tubes which connect saidupper drum and said first lower drum; a conventional boiler sectionhaving a second lower drum, an inlet, an outlet, a plurality of boilertubes which connect said upper drum and said second lower drum, and acombustion chamber defined by a portion of said plurality of boilertubes; a barrier between said plurality of boiler tubes in said heatrecovery section and said plurality of boiler tubes in said conventionalsection whereby heat transfer between said sections is restricted. 13.The system of claim 12 wherein said barrier is composed of metal. 14.The system of claim 12 wherein said barrier is composed of an insulatingmaterial.
 15. The system of claim 12 wherein said barrier is composed ofa combination of metal and insulating material.
 16. The system of claim12 wherein said heat recovery system is a gas turbine heat waste heatrecovery system and said inlet for the acceptance of heat input providesfor the acceptance of exhaust gases from a gas turbine engine.